Apparatus for purifying air



March 7, 1939. u. vA D'ANNUNzlo APPARATUS FOR PURIFYING AIR Filed oct. 50, 1957 4 sheets-s119611 March 7, 1939. u. v. D'ANNuNzlo I 2,150,027

-APPARATUS FOR PURIFYING AI Filed oct. so, 1937 4 sheets-'sheet 2 .4 l [ur/1 Ql/ March 7, 1939.

U. V. D'ANNUNZIO APPARATUS FR PURIFYING -AIR '4 .Filed oo t. 50, 1937 4 sheets-sheet 3 March 7, 1939. u. v. D'ANNuNzlo APPARATUS FORv PURIPYING AIR Filed oct. so, 1937 4 sheets-sheet 4 Patented Mar. 7, 1939 l.i1ram'l'usironPumr'ylrmr'lim v Ugo aannunno, New York, N. Y. Application October 30, 1937, Serial No. 171,827

suing from a pipe or duct at a certain velocity,

from solid particles carried in suspension thereby.

vThere are.v in practice many instances where the removal of solid particles fromair is necessary or desirable. For instance, in industrial plants the dust produced by the operation of polishing and grinding machines is usually carried away by air suction, the current of air being generated by a suction fan andthe dust charged air being delivered to some point outside the building. The quantity of dust carried away by the air in such installations is quite considerable, and it is imperative that the air be freed from such dust before it is once more discharged into the surrounding atmosphere.

In some other cases it is necessary to free air from dust and other solid matter in order to prevent the abrasive action of such dust when the air is delivered to a. delicate piece of machinery such as, for instance, an automotive engine in tractors and other appliances, which due to their conditions of service are likely to beoperated in dusty surroundings.

Another instance where purication of the air is desirable, in fact essential, is in air conditioning installations where air should be delivered in a washed and filtered condition..

The collection of sand, dust and other solid matter suspended in air in motion constitutes a serious problem, especially when the quantity of solid matter suspended in the air is considerable and when the gritty action of even a small quantity of dust might seriously -impair the life and performance of an expensive engine.

In large dust collecting installations the air is usually led to a chamber where its velocity is reduced so as to allow the major part of the solid matter suspended in the'air to settle. 'I'his action is-usually supplemented by that of ltering screens interposed in the path of the air and finally by discharging the partially purified airI 11 claims. .(ol. zei-so) the surface of the liquid, preventing direct contact between the liquid and the dust discharged thereagainst by the air, so that the dust removing action will practically cease.

When, instead of being discharged against the 5 surface of the liquid, the air is discharged at a certain depth within the liquid, the resulting air bubbles will constitute so many air pockets which will prevent direct contact between the dust and the surrounding liquid, so that the air will usually rise from the surface of the liquid still `charged with dust. y

'Ihe primary object of this invention lis to provide a novel and improved method of freeing air in motion from solid particles suspended therein, 15 whereby the air will be purified in a continuous and efficient manner. v

Another object is to provide a. method for re. moving solid andsemi-solid particles from air in motion whereby the air is caused to impinge against a surface covered with a lm of suitable liquid, said surface being continuously renewed and being freed of the matter adhering thereto before it once more reaches the point where the air impinges thereaga-inst.

A further object is to provide a novel and improved yair purifying apparatus, including means for presenting a moist surface directly opposite an outlet from which air to be purified is discharged, said moist surface being continuously renewed and the solid matter collecting thereon being continuously removed so as to permanently present a clean,eilicient liquid film directly opposite the discharged air.

A still further object is to provide a novel'and 35 improved apparatus, consistingof relatively few parts, adapted to efiiciently remove dust and other solid particles carried in suspension by a current of air or gas in a continuous manner. Other objects and advantages of the present 40 inventionwill more fully appear asthe description proceeds and will be set, forth and claimed in the appended claims.

My invention is illustrated by way of example in the accompanying drawings, in which: Y

Fig. -1 is a vertical longitudinal section of a dust collecting apparatus embodying my invention; i

Fig. 2 is a front view in elevation of the same; 50

Fig. 3 is a vertical transversalv section of the same through line 3-3 of Fig. 1;

Fig. 4 is a vertical transversal section of the same through line 4 4 of Fig. 1;

Fig. 5 is a vertical longitudinal section of an- 5'5 other 'form of apparatus, also embodying my invention; and

Fig. 6 is a vertical cross section of a device especially adapted for purifying the air supplied to an internal combustion engine.-

An apparatus embodying my invention comprises essentially an element having a traveling surface in close proximity of and directly opposite to an outlet or nozzle through which the air to be purified is supplied under pressure to the apparatus, means for continuously maintaining said traveling surface in a moist condition, means for freeing said surface of solid matter adhering thereto and` means for delivering the purified air or gas to a point of discharge.

Referring to Figs. 1 to 4, which illustrate an apparatus such as might be-usedas part of a dust collecting system in an industrial plant, IU designates a casing or frame formed with two separate chambers II, I2`, each forming a unit of the air purifying system.

'Ihe .air or gas to be puriiied is supplied under pressure to the apparatus through a pipe Il, terminating in a nozzle I4, having its outlet II opening iny proximity of and directly opposite the. surface of a drum I I, rotatably. mounted within chamber II.

Said drum isy carried by a shaft-|1, running from front to rear through chamber Il, the rear end of said shaft carrying a wormwheel I8. which is driven byv a worm I9, carried by a driving shaft 20. 'I'he rotation of driving shaft 20 will thus be vtransmitted to shaft I1 so as to cause shaft I1 and drum I6 carried thereby to rotate in a clockwise direction, as indicated by the arrow in Fig. 1.`

The bottom of chamber II is preferably slanting to form a well 2|, having a discharge outlet 22, controlled by a normally closed valve 23.

Chamber II is partially filled with a suitable liquid 24, within Awhich the lower partrof drum I6 is partly submerged. As a result the surface of drum I6 is continuously kept in a moist condition while the drum rotates within the liquid, so that the air discharged from the outlet I of nozzle I4 'will directly impinge against a continuously renewed moist surface.

Due to the momentum imparted by the velocity of the air to the solid particles therein suspended, such solid particles will violently strike against the -moist surface of the drum, and will adhere to and be carried away by said surface. The

aid freed of the solid particles will rebound from thesurface of the drum and will continue its course through4 a pipe 2l extending from opening 26 at the top of chamber II.

As each point of the surface ,of the drum passes beyond outlet Il of nozzle I4, it will eventually reach a point where the edge 21 of a scraper 28 bears against the surface ofthe drum and removes therefrom the iiim of liquid charged with solid matter, causing the same to II and provided at one of its projecting ends with an arm I6.

Said arm 38 provides a means of attaching thereto a tension spring 31, which is -attached at its other end to eye-bolt I8 mounted in a lug 39 and adjustable by-means of nuts -40, 4I, in order to regulate the tension exerted by the spring and thus the pressm'e with which the scraper bears against jthe surface of the drum.

The filtering box should .be removed from time to time for cleansing purposes, because the foreign matter accumulating upon the screen or screens will eventually impair its filtering capacity; therefore, the front wall of chamber Il is preferably provided withv an opening through which' said filtering box ycan be inserted or removed, said opening being normally hermetically closed by means of a cover 42.

The liquid contained within chamber II, which can be supplied thereto through a pipe 4I, controlled by a valve 44, should possess such viscosity as maybe best suited for the purpose. Water will do in most cues when the dust partices are very small, but when heavier particles may be carried in suspension by the air to be purified, or when the percentage ofrsolid matter is relativeiyhigh, a liquid having a greater viscosity than that of water, such as, for instance, a mineral oil, is to be preferred.

While the character of the liquid used is av factor affecting the eillcient operation of the device, the quantity of liquid adhering to the surface of the drum is also to be regulated so as to prevent an excessive quantity of liquid from adhering to the surface of the drum. such as might result in some of the liquid being atomized by the impinging air and carried away by said air through the discharge pipe.

I, therefore, prefer to provide means for removing from the surface of the drum any liquid ,Whichf' might adhere thereto in excess of that necessary and sufficient for absorbing the solici particles projected against it by the impinging air. This object can be attained by causing a roller 45 to bear against the surface of the drum at a point in advance of the air discharge outlet I 5, said roller being mounted between a front and rear arm 46 carried by ashaft 41 running from front to rear through chamber II.

At its front end said shaft 41 carries an arm 48 to -the tip end of which is attached one end of a tension spring 49, the other end of which is attached to an eye-bolt 50 also mounted in lug 28, and adjustable by means of nuts 5I, 52, to regulate the tension exerted by spring 40 and consequently the pressure with which roller 45 bears against the surface of the drum.

The assembly of the elements so far described in itself constitutes a complete apparatus for carrying my method into practice. However, where large quantities of 'air are to be treated, or where the air is charged with a high percentage of impurities, a single treatment may not bev suillcient to remove all of the foreign matter from the air. In such cases, therefore, it may be desirable to subject thelair to two or more successive treatments in order to nally deliver the air to the point of discharge in the desired degree of purity. v

Therefore, the apparatus illustrated in Figs. l to 4 is shown as being composed of two units in series, the second unit being constituted by the chamber I2 and the other elements mounted within said chamber, said elements comprising drum I6', mounted on shaft I1', scraper 28 mounted on shaft 35', filtering box 30'-, and pressure roller 45' for removing the excess of liquid from the surface of the drum.

The air or gas discharged in a partly puriiied condition into pipe 25 is once more discharged at the other end of said pipe through a nozzle I4', having its outlet I5'y opening in proximity of and directly opposite the sin'face of rotating drum I6', the lower part of said drum, likein the previous case, being submerged in the body of liquid 24.

The air is finally discharged from chamber I2 through a discharge pipe 25'.

The treatment of the air or gas to be purified in successive steps not only offers-the advantage of greater efciency, but also makes it possible to use liquids of different viscosity in the successive steps. For instance', the liquid contained in chamber II may-have a greater viscosity than that contained in chamber I2, so that the major part of the heavier particles may be .retained by the surface of drum I 6 and the air reaching chamber I2 will be charged with only some of the lighter particles, which can be best absorbed by a less viscous liquid.

Shaft I1' and other shafts carrying the drums of additional units, if any, can be driven by the first shaft I1 at the same or at different speeds, as the case may be. This can be done in any suitable manner, for instance, by providing shaft I1 with a sprocket 53, connected by a chain 54,

to a similar sprocket 53'v mounted on shaft I1. The discharge outlets 22, 22', of chambers II, I2,.-are, of course, provided for drainage of the liquid from said chambers for filtering or'renewal purposes. The apparatus is, therefore,'mounted so as to be raised from the ground and is accordingly'shown as being supported by columns 55; 5G, 51, making it possible to leave a clearance under the outlets 22, 22' for the placement of tanks within which the liquids 24, 24 canbe discharged. It is to be understood that the runways Von which filtering boxes 30, 30V are supported and the openings served by covers 42, 42', are at a level above the level of the liquid within the chambers so that the removal of either cover will not affect the status of the liquid Within the corresponding chamber.

In Fig. 5 I show an alternative form of apparatus also embodying my invention, invwhichy the casing 58 forms a single chamber 59, partly filled with liquid 60, the bottom of said chamber being provided with anoutlet BI, controlled by a valve 62, for the purpose of drainage.

Within the chamber are rotatably mounted two longitudinally spaced drums 63, 64, in proximity of the top 55 of the chamber. An endless belt 66 runs over said drums, said belt being long enough to extend downwardly from said drums into the body of liquid 60. The belt is'maintained under sufficient tension tobe driven'by one of the drums B4 by an idle roller 61, resting with its weight uponthe lower part ofthe belt.

The drum 64 is carried by a shaft 68, upon which is mounted a wormwheel, shown in dotted lines in Fig. 5, said wormwheel being mounted upon the shaft externally of the wall of the chamber and being driven by a worm 10, mounted on a shaft 1 I having a driving pulley 12.

The upper portion of the belt-extending be- `tween the two drums is preferably supported by a solid surface 13, forming a backing therefor, so as to enable the belt to function as a virtually rigid surface at the points where it is subjected to the impact of the lcurrent of air or gas.

Like in the previous case, the air or gas to be purified is supplied to the apparatus through a pipe 14 directing the air ,or gas to the outlet 15 of its nozzle portion 1i, said outlet being inproximity of and directly opposite the surface of the traveling belt. The partly purified air or gas is then redirected through inlet 11 of an intermediate pipe 1B to the outlet 19 of its nozzle 80, said outlet also being in proximity of and directly opposite the surface of the traveling belt.

Said air or gasis here subjected to Ia second purifying treatment which will remove from said air or gas the residual solid particles which were not previously removed, the purified air or gas being flnallyydischarged through inlet 8| of discharge pipe 82.

It will be observed that in all the arrangements illustrated the airor gas is discharged from the nozzle at right angles to the surface of the belt or drum so that it will impinge directly thereagainst. Furthermore, in order to make sure that part of the air or gas will not be deiiected sidewise towards a laterally spaced outlet, without striking the moist surface with a full impact, the course of said air or gas is sharply reversed after it strikes the moist surface. In the arrangement shown this result is obtained not only by disposing the outlet for the air after it has been discharged by the nozzle against the moist surface, in proximity of and directly oppositey the said surface, but also by disposing said outlet in close proximity of the nozzles outlet, while pre- '4 venting said air or gas from following any other in order to reach an outlet located at a distance therefrom, such a laterally deflected portion would not be freed of the major part of its impurities, only the film of such air or gas coming in actual contact with the moist surface being acted upon, and then not as efdciently as when the 'air or'gas strikes said moist surface with the full impact due to its original direction of discharge.

As indicated in the drawings, the successive discharges of the air or gas against the belt "preferably take place in reverse direction to thatof the belts travel. Due to the fact that drum 64 rotates in aclockwise direction. the upper or active portion/ of the belt will travel from left to right, so that it will pass first in front of the second discharge outlet 19l and then in front of the rst discharge outlet 15. 'l

By virtue of this arrangement'the part of the belt which has freshly emerged from the body of liquid and is still free of solid matter is caused to perform the seco-nd or nishing step of the cleansing operation so that itwill be in the best condition for removing the lighter dust particles still suspended in the air or gas at this stage.- Since the residual quantity of solid matter still suspended in the air or gas at this stage is relatively small, the surface of the belt still remains in a sufficiently moist and receptive condition for lsubsequently retaining the major part of the solid matter contained -in the air or gas discharged through the first outlet 15.

Like in the previous case, the surface of the .belt is subsequently `freed of the solid matter adhering thereto by means of a scraper 88 carried by a pivotal shaft 84, said scraper bearing against the belt at a preferably adjustable pressure induced in any suitable manner, for instance,

by means of a spring, as explained in connection with scrapers 28, 28 of the apparatus previously described.

The matter thus removed from the surface of the belt will run down thefback surface 85 of the scraper and into a filtering box 86, the bottom of which is formed by a ltering screen 81. Said filtering box is preferably removable endwise, as previously explained, Aior cleansing purposes and when in operation will redirect the filtered liquid to the bottom of chamber 58 through perforated wall 88. In this case also I prefer to provide suitable means for removing from the surface of the belt any excess liquid that should adhere thereto before said surface reaches the discharge nozzles. To this end I provide a roller 89, carried by arms 98, mounted on a pivotal shaft 9|, said roller bearing withV a preferablyy adjustable pressure against the surface of the belt at a point in advance of nozzle outlet 18, the pressure of said roller being exerted directly against that part of the belt which rides over drum 83.

Liquid may be supplied to chamber 68 through a supply pipe 82, controlled by a valve 88, or in any other suitable manner.

It is to be understood that also in this case the purifying steps may be more or less than two, according to the quantity andnature of the solid matter to be removed from the air or gas, and according to the degree of purity to be obtained in the air or gas when finally discharged.

In many instances the quantity of solid matter contained in the air or gas is relatively small and a single step of purification may be sufiicient for the purpose. For instance, lin the opration of an internal combustion engine the presence of any quantity of gritty particles, no matter how small, in the air supplied to the cylinders is highly objectionable. Therefore, although the percentage of solid matter is generally small its removal is highly desirable, a single purifying step being usually sumcient to thoroughly clean the air.

A device suitable for use in connection with an explosion engine, such as may be used in a tractor, truck or airplane, is shown in Fig. 6. Such device is composed practically of the same elements as the apparatus previously described except that the device can be made reasonably small s o as to permit of its being made a part of the equipment ofrthe automotive device served' thereby.

Referring to Fig. 6, it will be seen that the device comprises a casing 8l, having a removable bottom part 88, forming a container for the body of liquid 88, within which is submerged the lower part of the rotating drum 81 mounted within said casing. The air sucked in by the engine through pipe 88 is supplied from the atmosphere through lmet pipe 88. terminating in a nozzle |88 having an outlet III opening in proximity of and directly opposite the surface of the drum 81.

After violently impinging against the surface of the drum the air is deflected through inlet |82 into pipe 88 leading to the carbureter and then' to the engine. -The rotation of drum 8l can be produced in any suitable manner, for instance, by operatively connecting its shaft |88 to some moving part of the engine through the gear |84, shown in dotted lines in the figure. A

Also in this case the solid matter adhering to the surface of the drum is removed by a scraper |88, which will discharge the same into a com- 2,1so,oa7

partment I 06 of the receptacle formed by thev bottom portion 95, said compartment being separated from the main part of the receptacle byy a filtering screen |01.' When the liquid within said receptacle i'sato be replaced by new liquid it is suiiicient to remove and then replace the bottom 95, which is secured to the casing by means of screws |88.

Suitable means are also preferably provided for removing the excess liquid from the surface of the drum at some point in advance of the nozzle outlet, such means also in this case being represented by a roller |89, mounted between arms lill, said roller bearing at a preferably adjustable pressure against the surface of said drum.

The surface of the drum or other impurity collecting member can be moistened in ways other than by having its lower portion submerged in a liquid of the proper viscosity, so that in order to carry my invention into practice it is not absolutely necessary that said collecting member be mounted on a horizontal shaft, or shafts.

In some installations Where air may be directly discharged into the atmosphere after having been` freed of the solid or semi-solid particles therein suspended, it is also possible to omit the use of a discharge conduit for the purified air, such, as shown at 25' in Fig. 1, the air being discharged directly through the opening in the casing.

The inventive idea may in other respects be applied in ways different from those shown in the drawings; said drawings should, therefore, be understood as being intended for illustrative purposes only and not in a limiting sense.

I, accordingly, reserve the right to carry my invention into practice in all those ways and manners which may enter, fairly, into the scope of the appended claims.

l. Apparatus for freeing a gas from small particles therein suspended, comprising a casing, an impurity collecting member having an endless surface, mounted within said casing, a nozzle for discharging said gas at a certain velocity directly against said surface, means for actuating said member so as to cause said surface to continuously travel in'a given direction, means for maintaining said surface in a moist condition adapted to retain particles carried by said gas impinging against the same, and a discharge conduit for the purified gas deflected by said surface, the inlet of said conduit facing said surface at a point in close proximity of the outlet of said nozzle.

2,J Apparatus for freeing a gasfrom small particles therein suspended, comprising a casing. an impurity collecting member having an endless surface, mounted within said casing, a nozzle for discharging said gas at a certain velocity directly against saidk surface, means for actuating said member so as to cause said surface to continuously travel in a given direction, means for maintaining said surface in a moist condition adapted to retain particles carried by said gas impinging against the same, means for removing said particles from said surface directly as they are collected thereon, and a discharge conduit for the puried gas deflected by said surface, the inlet of said conduit facing said surface at a point in close proximity of the outlet of said nozzle.

3. Apparatus for freeing a gas from small particles therein suspended, comprising a casing, an

4impurity collecting member having an endless surface, mounted within said casing, a nozzle for discharging said gas at a certain velocity directly against said surface, means for actuating said member so as to cause said surface to continuously travel in a given direction, a body of liquid at the bottom of said casing reaching a level suflicient to submerge the lower portion of said surface, means for removing from said surface the liquid lm and particles adhering thereto, directly as said particles are collected upon said surface, and means for separating the liquid from the particles, and for redirecting the liquid to the body thereof at the bottom of the casing.

4. Apparatus for freeing a gas from small particles therein suspended, comprising a casing, an impurity collecting member. havingan endless surface, mounted within said casing, a nozzle for discharging said gas at a certain velocity directly against said surface, means for actuating said member so as to cause said surface to continuously travel in a given direction, a body of liquid at the bottom of said casing reaching a level suincient to submerge the lower portion of said surface, means for removing from said surface the liquid film and particles adhering thereto, directly as said particles are collected upon said surface, means for separating the liquid from the particles, and for redirecting the liquid to the body thereof at the bottom of the casing, and a discharge conduit for the purified gas deflected by said surface.

5. Apparatus for freeing a. gas from small particles therein suspended, comprising a casing, an impurity collecting member having an endless surface, mounted within said casing, a nozzle for discharging said gas at a certain velocity directly against said surface, means for actuating said 'member so as to cause said surface to` continuously travel in a given direction, a bodyi of liquid at the bottom of said casing reaching a level suilicient to submerge the lower portion of said surface, means for removing from said surface the liquid nlm and particles adhering thereto, directly as said particles are collected upon said surface,

means for separating the liquid from the particles, and for redirecting theliquid to the body thereof v at the bottom of the casing, and means for removing the excess liquid from said surface at a point in advance of said nozzle.

6. Apparatus for freeing a gas from small particles therein suspended, comprising a casing, an. impurity collecting member having an endless surface, mounted within said casing, a nozzle for discharging said gas at a certain velocity directly against said surface, means for actuating said member so as to cause said surface to continuously travelv in a given direction, a body of liquid at the bottom of said casing reaching a level sumcient to submerge the lower `portion of said surface, means for removing from said surface the liquid film and particles adhering thereto, directly as said particles are collected upon said surface,

and a removable ltering box for separating the liquid from the particles,'and for redirecting the y liquid to the body thereof at the bottom of the casing.

'7. Apparatus for freeing a gas from 'small particles theren suspended, comprising a casing having a plurality of chambers, a drum rotatably mounted within each chamber, a nozzle for discharging said gas at a certain velocity directly against the surface of each drum, a body of liquid at the bottom of each chamber reaching a level sufcient to submerge the lower portion of the corresponding drum, means for removing from the surface of each drum the liquid film and particles adhering thereto, means for separating the liquid from. the particles and for redirecting the liquid to the body thereof at the bottom of the corresponding gas at a certain velocity through each opening' directly against said surface, a conduit for discharging through each opening the gas deflected by said surface', said nozzle and conduit together enclosing the mouth of each opening and forming with the portion of said surface exposed through said opening a virtually closed flow reversing channel for said gas, the discharge conduit for the gas deflected by said surface through each opening'but the last leading to the nozzle serving the next opening, the discharge conduit from the last opening leading the purified gas to a point of delivery, and means for actuating said member so as to cause said surface to continuously travel in a given direction.

9, Apparatus for freeing a gas from small p articles therein suspended, comprising a casing having a plurality of openings,^an impurity collecting member having an endless surface, mounted within said casing so that its surface virtualy closes said openings, means for maintaining said surface in a moist condition, a nozzle for discharging said gas at a certain velocity through said opening directly against said surface, a conduit for discharging through each opening the gas deflected by said surface, said nozzle and conduit together enclosing the mouth of each opening and forming with theportion of said surface exposed through said opening a virtually closedy flow reversing channel for saidgas, the discharge conduit for the gas deflected by said surface through each opening but the last leading to the nozzle serving the next opening, the discharge conduit from the -last opening leading the purifled gas to a point of delivery, and means for actuating said member so as to cause said surface to continuously travel in a given'direction, said nozzles and discharge conduits forming a step by step passage for said gas from the first to the last opening and causing said gas to travel in a direction opposite to 'that Aof the travel of said surface.

- together enclosing the mouth of each opening and forming with the portion of said surface exposed through said opening a virtually closed flow -reversing channel for said gas, the discharge conduit for the gas deiiected by said surface through. each opening but the last leading to the nozzle serving the next'opening, the discharge conduit from the last opening leading the purified gas toa point of delivery, meansfor actuating said member so as to cause said surface to continuously travel in a given direction, and means for removing from said surface the liquidillm and particles adhering thereto, as said particles are collected upon said surface.

11. Apparatus for freeing a gas from small particles therein suspended, comprising a negarle for discharging said gas under pressure, a discharge conduit for said gas having its inlet in close proximity to the outlet of said nozzle, an impurity collecting member having an endless surface diin agiven direction, and means for maintaining 5 A said surface in a moist condition adapted to retain particles carried by said gas impinging against theV same.

` UGO V. DANNUNZIO. 

